Some examples of the use of the X-ray powder diffraction method in quantitative analysis; the determination of small amounts of (a) calcium oxide in magnesium oxide; (b) zinc oxide in zinc sulphide

The Analyst ◽  
1945 ◽  
Vol 70 (830) ◽  
pp. 166 ◽  
Author(s):  
H. P. Rooksby
Keyword(s):  
Zinc Oxide ◽  
Quantitative Analysis ◽  
Magnesium Oxide ◽  
Calcium Oxide ◽  
Powder Diffraction ◽  
Diffraction Method ◽  
Zinc Sulphide ◽  
X Ray

A standardless X-ray diffraction method for the quantitative analysis of multiphase mixtures. II. Application to non-infinitely thick samples

2002 ◽  
Vol 35 (5) ◽  
pp. 600-605 ◽  
Author(s):  
Eva T. Gomez ◽  
Teófilo Sanfeliu ◽  
Jordi Rius
Keyword(s):  
Quantitative Analysis ◽  
Least Squares ◽  
Powder Diffraction ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
Airborne Particulates ◽  
X Ray ◽  
Experimental Values

In 1987, Rius, Plana & Palanques [J. Appl. Cryst.(1987),20, 457–460] devised an X-ray powder diffraction method based on the `least-squares' determination of calibration constants using only the diffracted intensities and the calculated absorption coefficients of the components. This method was developed for `infinitely thick' samples, a condition which is seldom met by airborne particulates because of the small amount of material normally available. Since the analysis of such samples may become one of the principal applications of the method, this condition represents a serious limitation. The simplest way to overcome this limitation is by correcting the measured intensities. This can be done either by direct measurement of the sample transmission, or alternatively, by using refined transmission values. In the latter case no experimental values are necessary. With the help of some test calculations, the viability of both possibilities has been explored.

scholarly journals Magnetically Oriented Powder Crystal to Indexing and Structure Determination

2014 ◽  
Vol 70 (a1) ◽  
pp. C1560-C1560
Author(s):  
Fumiko Kimura ◽  
Wataru Oshima ◽  
Hiroko Matsumoto ◽  
Hidehiro Uekusa ◽  
Kazuaki Aburaya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Lattice ◽  
Powder Diffraction ◽  
Diffraction Method ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Lattice Parameters

In pharmaceutical sciences, the crystal structure is of primary importance because it influences drug efficacy. Due to difficulties of growing a large single crystal suitable for the single crystal X-ray diffraction analysis, powder diffraction method is widely used. In powder method, two-dimensional diffraction information is projected onto one dimension, which impairs the accuracy of the resulting crystal structure. To overcome this problem, we recently proposed a novel method of fabricating a magnetically oriented microcrystal array (MOMA), a composite in which microcrystals are aligned three-dimensionally in a polymer matrix. The X-ray diffraction of the MOMA is equivalent to that of the corresponding large single crystal, enabling the determination of the crystal lattice parameters and crystal structure of the embedded microcrytals.[1-3] Because we make use of the diamagnetic anisotropy of crystal, those crystals that exhibit small magnetic anisotropy do not take sufficient three-dimensional alignment. However, even for these crystals that only align uniaxially, the determination of the crystal lattice parameters can be easily made compared with the determination by powder diffraction pattern. Once these parameters are determined, crystal structure can be determined by X-ray powder diffraction method. In this paper, we demonstrate possibility of the MOMA method to assist the structure analysis through X-ray powder and single crystal diffraction methods. We applied the MOMA method to various microcrystalline powders including L-alanine, 1,3,5-triphenyl benzene, and cellobiose. The obtained MOMAs exhibited well-resolved diffraction spots, and we succeeded in determination of the crystal lattice parameters and crystal structure analysis.

scholarly journals Quantitative Phase Analysis by X-ray Diffraction—Doping Methods and Applications

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 27 ◽  
Author(s):  
Stanko Popović
Keyword(s):  
Quantitative Analysis ◽  
Phase Analysis ◽  
Powder Diffraction ◽  
Phase Fraction ◽  
Quantitative Phase Analysis ◽  
Intermetallic Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Phase

X-ray powder diffraction is an ideal technique for the quantitative analysis of a multiphase sample. The intensities of diffraction lines of a phase in a multiphase sample are proportional to the phase fraction and the quantitative analysis can be obtained if the correction for the absorption of X-rays in the sample is performed. Simple procedures of quantitative X-ray diffraction phase analysis of a multiphase sample are presented. The matrix-flushing method, with the application of reference intensities, yields the relationship between the intensity and phase fraction free from the absorption effect, thus, shunting calibration curves or internal standard procedures. Special attention is paid to the doping methods: (i) simultaneous determination of the fractions of several phases using a single doping and (ii) determination of the fraction of the dominant phase. The conditions to minimize systematic errors are discussed. The problem of overlapping of diffraction lines can be overcome by combining the doping method (i) and the individual profile fitting method, thus performing the quantitative phase analysis without the reference to structural models of particular phases. Recent suggestions in quantitative phase analysis are quoted, e.g., in study of the decomposition of supersaturated solid solutions—intermetallic alloys. Round Robin on Quantitative Phase Analysis, organized by the IUCr Commission on Powder Diffraction, is discussed shortly. The doping methods have been applied in various studies, e.g., phase transitions in titanium dioxide, biomineralization processes, and phases in intermetallic oxide systems and intermetallic alloys.

Synthesis and crystal-structure determination of fibrillar methylammonium trimolybdate hydrate

2007 ◽  
Vol 22 (3) ◽  
pp. 241-245 ◽  
Author(s):  
B. Włodarczyk-Gajda ◽  
A. Rafalska-Łasocha ◽  
W. Łasocha
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Synthesis Method ◽  
Diffraction Method ◽  
Orthorhombic Space Group ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Novel Synthesis

A novel synthesis method of fibrillar trimolybdates with the use of Ag2Mo3O10∙2H2O as a precursor has been used successfully to synthesize methylammonium trimolybdate, (CH3NH3)2Mo3O10∙H2O. The crystal structure of this compound was determined by X-ray powder diffraction method and refined by the Rietveld method. The compound is orthorhombic, space group Pnma (62), with a=11.241(3), b=7.585(1), and c=15.516(4) Å. The redetermined crystal structure of the precursor and the structure of the title compound are compared and discussed.

The Determination of Zinc Oxide in Rubber Vulcanizates by X-Ray Diffraction

1960 ◽  
Vol 33 (3) ◽  
pp. 890-898
Author(s):  
Stephen H. Laning ◽  
Melvin P. Wagner ◽  
John W. Sellers
Keyword(s):  
Zinc Oxide ◽  
Quantitative Analysis ◽  
Analytical Method ◽  
Direct Determination ◽  
Zinc Stearate ◽  
Photographic Film ◽  
Reaction Products ◽  
X Ray

Abstract Zinc oxide is a necessary component in most accelerator-sulfur vulcanization systems. While it is not an accelerator, its presence leads to increased modulus, i.e., tighter cures. The manner in which it can effect this better cure is not completely clear. Some insight into the role of zinc oxide has been gained through the analysis of the vulcanizate for reaction products of zinc, such as zinc stearate, the zinc salts of the accelerators, and zinc sulfide. However, these products may not account for all of the zinc oxide which has reacted. An analytical method for the direct determination of unreacted zinc oxide in vulcanizates was therefore needed. The determination of zinc oxide in rubber vulcanizates has received scant attention. Wet-chemical techniques for analysis of the sample after ashing provide only the total amount of zinc from which the amount of unreacted zinc oxide cannot be determined. Endter has reported the use of the Debye-Scherrer x-ray technique for the identification of zinc oxide in rubber samples. While similar to the method developed in this laboratory, Endter employed photographic film for recording the diffraction pattern, and special sample preparation was required to accommodate the photographic technique. This method was satisfactory for qualitative identification of zinc oxide, but was difficult to use for quantitative analysis. Subsequent to this investigation Hagino et al. described the use of x-ray diffractometry for the determination of the mixing ratio of ingredients compounded in rubber. This method was also suggested for the quantitative analysis of zinc oxide, but no studies were reported. During a study in this laboratory to determine the role of zinc oxide in the vulcanization of rubber, a new analytical method, based on x-ray diffractometry, was developed. The method was rapid, nondestructive, and simple. The data were reliable and accurate.

scholarly journals Quantitative Determination of Mineral Phases by the X-Ray Powder Diffraction Method in Organo-Mineral Substrates (Digestate, Compost and Ash From Biomass)

2014 ◽  
Vol 62 (5) ◽  
pp. 905-909 ◽  
Author(s):  
Milan Geršl ◽  
Jan Mareček ◽  
Dalibor Matýsek ◽  
Tomáš Vítěz ◽  
Pavol Findura
Keyword(s):  
Powder Diffraction ◽  
Plant Nutrition ◽  
Chemical Elements ◽  
Renewable Energy Sources ◽  
Diffraction Method ◽  
Energy Sources ◽  
Soil Processes ◽  
X Ray ◽  
Mineral Phases

In the field of energetics and renewable energy sources, fertilizers, remediation and recultivation, waste management and other, biomass is widely studied and used these days. Determining the mineral phases present in the biomass is essential for determining the binding of chemical elements from which further derives its availability or unavailability for soil processes, plant nutrition or behaviour in technological processes. Semiquantitative phase analyses were carried out by the X-ray powder diffraction method (XRD).

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